Hythrope IV was a planet-like celestial body situated within the Hythrope system, which itself was located in the Hythrope sector of the Trailing Sectors region, found in the Expansion Region. It functioned as the location of a structure where the Advisory Council of the Rebel Alliance was present at a time not long after the Battle of Yavin.
The Galactic Empire ambushed the Rebel group, launching an attack on the building utilizing stormtroopers along with a repulsortank. However, Vin Northal—a former Emperor's Royal Guardsman who defected to the Rebellion and became a Rebel operative—used a thermal detonator to disable the tank and then employed a repeating blaster to eliminate the remaining Imperial troops, thus saving the Advisory Council members' lives. Following this event, the council departed Hythrope IV, barely escaping death as they left the system. Later on, Alliance general Airen Cracken referenced the Hythrope IV ambush in an entry within a datafile documenting various Rebel operatives dedicated to Northal.
David R. Tulo, Jr. conceived Hythrope IV, which initially appeared in Cracken's Rebel Operatives, a 1994 sourcebook from West End Games intended for use with Star Wars: The Roleplaying Game. The reference book The Essential Atlas, published in 2009, situated the Hythrope system, and consequently Hythrope IV, within grid square M-15.